In a known manner, axleboxes are mounted on railway vehicle such as trains, in particular on locomotives, passenger coaches, and freight cars. Generally, a railway vehicle includes several bogies. Each bogie comprises a frame, two (or more) wheelsets and four (or more) axleboxes. Each wheelset comprises an axle supporting two wheels. The axlebox is the linking elements between the rotating wheelset and the quasi-static frame of the bogie. The axlebox comprises supports for off-set helical springs housing, and a housing receiving a bearing unit.
Bearing unit is generally clamped in housing by a back cover on the wheel end, an axle passing through the back cover and being supported in rotation by the bearing unit. Generally, back cover is securely fixed to housing by four studs screwed in housing threaded holes, and then blocked by washers and nuts. Studs are preferably used than screws because of the reduced axial space at the vicinity of a wheel.
However, studs are much more expensive than screws. Another disadvantage is that studs have to be screwed in housing before assembly of back cover, then adding a preliminary step to the assembly process. Furthermore, each axlebox comprises four sets of locking means, each set having three parts: stud, washer, nut. It implies a large number of spare parts on assembly line of axlebox manufacturer and to follow for maintenance and inventory management.